fix some fuzz

src/pathops/SkPathOpsCommon.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "SkAddIntersections.h"
 #include "SkOpCoincidence.h"
 #include "SkOpEdgeBuilder.h"
 #include "SkPathOpsCommon.h"
@@ skipping 284 matching lines @@
         return false;
     }
     // mark spans of coincident segments as coincident
     coincidence->mark(DEBUG_COIN_ONLY_PARAMS());
     // look for coincidence lines and curves undetected by intersection
     if (missing_coincidence(contourList  DEBUG_COIN_PARAMS())) {
         (void) coincidence->expand(DEBUG_PHASE_ONLY_PARAMS(kIntersecting));
         if (!coincidence->addExpanded(DEBUG_COIN_ONLY_PARAMS())) {
             return false;
         }
-        coincidence->mark(DEBUG_PHASE_ONLY_PARAMS(kWalking));
+        if (!coincidence->mark(DEBUG_PHASE_ONLY_PARAMS(kWalking))) {
+            return false;
+        }
     } else {
         (void) coincidence->expand(DEBUG_COIN_ONLY_PARAMS());
     }
     (void) coincidence->expand(DEBUG_COIN_ONLY_PARAMS());
 
     SkOpCoincidence overlaps(globalState);
     safetyHatch = SAFETY_COUNT;
     do {
         SkOpCoincidence* pairs = overlaps.isEmpty() ? coincidence : &overlaps;
         // adjust the winding value to account for coincident edges
@@ skipping 12 matching lines @@
     sort_angles(contourList);
 #if DEBUG_COINCIDENCE_VERBOSE
     coincidence->debugShowCoincidence();
 #endif
 #if DEBUG_COINCIDENCE
     coincidence->debugValidate();
 #endif
     SkPathOpsDebug::ShowActiveSpans(contourList);
     return true;
 }